Friday 28th February – Spreadsheeting well and tractoring poorly

March 13, 2014

Last day today and I’m not sure how I feel about it. Tim asked whether I’d like to stay longer given the chance and I replied I don’t generally play the ‘what if’ game (which is true, it’s pointless unless you can actually change something) but if the opportunity arose in the future I would definitely come back and would certainly consider staying longer than a fortnight so long as I could be useful around the farm and hopefully learn as much as I have this last fortnight.

After the usual morning checks and breakfast Tim and I headed out to complete what would be my last set of measurements from the fermenters and digesters. While Tim got on with the time-consuming titrating, I set to the dry matter analysis and then spent the time between samples finishing off the macros and spreadsheets Thorsten had asked for over the last few days.

Just before lunch we headed back to the house to send over what we’d finished and Thorsten showed us how he wanted the comparison data for the maintenance cost for the gas engines assimilated with the amount of operating hours and kWh generated. Thinking we’d probably need some help negotiating the huge spreadsheets in German (25MB in size!) we decided to have some lunch first.

True to form, lunch was a highly inclusive affair. The meal was pasta bake with salad and some leftover vegetables from yesterday and was very tasty, as were the three types of cake for dessert (the new addition being a very soft sponge cake slice with gooey faintly lemon-tasting icing with a splash of a liqueur of unknown flavour for good measure). As we finished our mains the three Sturms, Christian, Tim and I were then joined by the painters from upstairs as well as Suzie which meant the table was very packed but incredibly jovial. As Tim commented as we left after lunch, it would be rare for work(wo)men to be invited to join the dinner table as friends back home but it really seems a different way of life here, and very pleasant it is too!

After lunch we took the last electrics reading and headed back to the office for about 3 hours of serious spreadsheet work that involved us showing Thorsten the results from the two weeks and being able to pinpoint using the FOS/TAC, pH, temperature, gas analysis and electricity readings how things were changing through the whole process due to, for example, the addition of extra minerals, increasing the heating duty in the fermenter (massively increases the overall process efficiency) and how changing the addition of oxygen in attempt to control H2S also affects the other gas compositions and amount of auxiliary gas required by the gas engines. All in all it was fairly satisfactory to see things come together. We then moved on to comparing the actual cost variation of the gas engine (circa 38% efficient at converting thermal energy in the biogas to electricity) and the oil-injection gas engine (higher efficiency, reputedly 42%). After including a whole range of factors from capital costs, discount rate, range of costs of maize substrate, amount of oil needed, availability (and cost of lost revenue when out of service) and maintenance costs per kWh we were able to plot how much more efficient the more efficient engine needed to be to offset the extra cost of operating it against the price of maize (which governs the cost of gas entering the engine) and for this farm it turns out to be in the range of 4-7 % points, but for the current maize prices it’s towards the higher end of the scale. It’s pretty interesting to see how a higher efficiency engine doesn’t correlate to a more economical purchase.

So much spreadsheeting for two lines on a graph. Still, I reckon it was worth it in the end

So much spreadsheeting for two lines on a graph. Still, I reckon it was worth it in the end

We also showed Thorsten the gas analysis macro (explaining the frustration of the output from the analyser) and the pig-monitoring macro which he seemed pretty pleased with. So pleased in fact that he let us out to drive the loader and put a few bucketfuls of maize into the rotamat loader. I GOT TO DRIVE THE TRACTOR!

Me + tractor, Doing stuff. Yeahhhhhhhh

Me + tractor, Doing stuff. Yeahhhhhhhh

Sorry, a little excited there, but for city boys like Tim and I this is a lot of fun. I managed to drop over a tonne of maize into the hopper fairly successfully. Well, successfully if you don’t count the dozen (hand)shovelfuls that I managed to drop onto the tractor itself…oops!

....more practice needed, clearly!

….more practice needed, clearly!

After clearing up the mess Tim and I cleaned the lab as well and then put on a shirt for dinner at a thai restaurant in with Thorsten and Suzie to celebrate what has been a very successful (at least from where I’m sitting) fortnight. Thorsten very kindly bought dinner for us and the food itself was very tasty, even if the chips served with the thai salad were (I’m sure) bacon flavoured.

After a long day, a couple of white beers and the drive back (thanks Suzie for being the designated driver) to the farm we were all fairly shattered and we slumped into bed soon after barely even noticing the noise from the cows next door.


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